About

Adding line numbers to text datasets is a frequent requirement in programming, legal documentation, and data preparation. This tool automates the process, allowing you to turn a raw list of items into an ordered sequence instantly.

Whether you need to number lines of code for a tutorial, create a numbered list for a CSV file, or index a legal contract, this utility offers precision control. It handles large text blocks efficiently and preserves your original data structure.

Formulas

The underlying logic iterates through the text stream using the following algorithmic steps:

Step 1. Break the input stream into an array of strings using the newline character \n as the delimiter.
Step 2. Initialize a counter i = start_value.
Step 3. Iterate through the array. If Ignore Empty is active and the line is null, skip increment.
Step 4. Apply padding logic: String(i).padStart(width, '0').
Step 5. Concatenate Number + Separator + Line and rebuild the stream.

Reference Data

Format Style	Pattern	Example Output
Standard	`N. Content`	1. Apple
Parenthesis	`N) Content`	1) Apple
Zero Padded	`00N: Content`	001: Apple
Custom	`[N] - Content`	[1] - Apple

Frequently Asked Questions

Yes, the tool allows you to define a custom 'Start Value', which is useful for paginated data or continuing previous lists.

You can choose to either number empty lines (preserving the sequence) or skip them entirely using the 'Ignore Empty Lines' checkbox.

The tool runs client-side in your browser. It can comfortably handle 50,000+ lines depending on your device's available memory.